Pen



FIG. 1 is a front elevational view of the pen;

FIG. 2 is a rear elevational view thereof;

FIG. 3 is a left-side elevational view thereof;

FIG. 4 is a right-side elevational view thereof;

FIG. 5 is a top plan view thereof; and,

FIG. 6 is a bottom plan view thereof. 

CLAIM The ornamental design for a pen, as shown and described. 